Creating a constructor for an anonymous inner class : Anonymous inner class « Class Definition « Java Tutorial

1. Java Tutorial
2. Class Definition
3. Anonymous inner class

abstract class Base {
  public Base(int i) {
    System.out.println("Base constructor, i = " + i);
  }

  public abstract void f();
}

public class MainClass {
  public static Base getBase(int i) {
    return new Base(i) {
      {
        System.out.println("Inside instance initializer");
      }

      public void f() {
        System.out.println("In anonymous f()");
      }
    };
  }

  public static void main(String[] args) {
    Base base = getBase(47);
    base.f();
  }
}

Base constructor, i = 47
Inside instance initializer
In anonymous f()